In a photolithographic technique for manufacturing semiconductor devices, a photoresist liquid is applied to a semiconductor wafer or a substrate to form a resist film exposed in accordance with a predetermined circuit pattern, and the exposed pattern is developed so that a circuit pattern is formed in the resist film. There is a possibility that bubbles of nitrogen gas or particles (foreign matter) might come to be mixed in a process liquid such as a photoresist liquid. When a process liquid containing bubbles or particles is supplied to a wafer, application non-uniformity and/or defect may occur. Thus, a liquid processing apparatus for supplying a process liquid to a wafer is provided with a filter for filtering bubbles and particles mixed in a process liquid.
Some processing apparatuses include a liquid supply system of a circulation filtration type. Such liquid supply systems may include a first container configured to store a process liquid; a second container configured to store a process liquid; a first pump disposed in a first pipe connecting the first container and the second container and configured to send the process liquid stored in the first container to the second container; a first filter disposed in the first pipe; a second pipe connecting the first container and the second container; and a second pump disposed in the second pipe and configured to send the process liquid stored in the second container to the first container. Some of these liquid supply systems may include a buffer container of a process liquid; a circulation and filtration apparatus that sucks a part of the process liquid from the buffer container to filter it using a filter, and then returns the filtered process liquid to the buffer container; and a pipe through which the process liquid is sent from the buffer container or the circulation apparatus to a photoresist application apparatus.